Every piece of rental equipment you own is an investment. Some investments pay off quickly. Others never break even. And unless you're running the numbers, you genuinely cannot tell the difference.
Most equipment owners have a vague sense of how much they earn per month in total. What they don't have is a clear picture of how each individual item is performing. That distinction matters because your portfolio almost certainly contains both winners and losers, and the totals hide which is which.
This guide walks through how to calculate ROI on rental equipment from scratch, with real numbers and worked examples. No finance degree required.
The basic ROI formula
ROI at its simplest is the ratio of what you've earned to what you spent.
ROI = (Net Earnings / Purchase Cost) x 100
If you bought a lens for $2,000 and it has earned $1,400 in net rental income (after platform fees and discounts), your ROI is 70%. You've earned back 70% of what you paid.
This number tells you one thing clearly: how far along you are toward paying off the item. At 100%, the gear has paid for itself entirely. Every dollar earned beyond that is pure profit on the original investment.
Why net earnings, not gross
The most common mistake in calculating rental ROI is using gross rental income instead of net. Gross is the total charged to the renter. Net is what actually lands in your account after platform fees, multi-day discounts, and promotional credits are deducted. A detailed breakdown of Sharegrid's fees and payouts shows just how large this gap can be.
On Sharegrid, the gap between gross and net can be 30% to 50% on longer rentals. If you calculate ROI against gross numbers, you'll overestimate your return significantly.
Always use the payout amount, not the booking total.
Payback percentage: the number that matters most
Payback percentage is a more intuitive version of ROI for rental equipment. It answers the question: how much of this item's purchase price have I earned back?
Payback = (Total Net Earnings / Purchase Cost) x 100
A payback of 86% means you've earned back 86 cents of every dollar you spent. At 100%, the item has paid for itself. At 150%, you've earned 50% more than you paid.
This framing is more useful than traditional ROI for rental owners because the primary financial question isn't "what's my percentage return" in the abstract. It's "has this thing paid for itself yet, and if not, how close is it?"
Worked example: camera body
Let's work through a real scenario.
Item: Blackmagic Pocket Cinema Camera 6K Pro
Purchase cost: $2,495
Rental history over 24 months:
- 24 individual rentals
- Average net payout per rental: $89
- Total net earnings: $2,145
Payback: $2,145 / $2,495 = 86.0%
This camera has earned back 86% of its purchase price in two years. At the current earning rate (about $89 per month average), it will fully pay for itself in roughly three more months.
Effective daily rate: The camera rented for a total of 44 days across those 24 rentals. $2,145 / 44 = $48.75 per rental day after fees and discounts.
Average rental length: 44 days / 24 rentals = 1.8 days per rental.
These secondary metrics are useful for understanding how the item is being used. Short average rental length means lots of single-day or weekend bookings. Longer averages suggest weekly or production-length rentals.
Worked example: lens
Item: Canon EF 16-35mm f/2.8L III USM
Purchase cost: $2,199
Rental history over 24 months:
- 19 rentals
- Average net payout per rental: $62
- Total net earnings: $1,186
Payback: $1,186 / $2,199 = 53.9%
This lens is about halfway to paying for itself after two years. At $62 per rental average, it needs approximately 16 more rentals to break even, which at the current booking rate of about one per month means roughly 16 more months.
The lens has booked less frequently than the camera body but holds its value better. A Canon 16-35mm f/2.8L purchased for $2,199 is still worth approximately $1,700 to $1,800 used. If you factor in resale value, the total return picture changes.
Adding resale value: total return ROI
For a complete picture, factor in what the item is worth today.
Total Return = (Net Earnings + Current Resale Value - Purchase Cost) / Purchase Cost x 100
Using the lens example:
Total Return = ($1,186 + $1,800 - $2,199) / $2,199 = 35.8%
Even though the lens has only earned back 54% of its cost through rentals, when you include its resale value, you're up 36% overall. You own an asset worth $1,800, and you've collected $1,186 in rental income. Your total position is $2,986 on a $2,199 investment.
This is the number that answers the question: "If I sold this today, would I come out ahead?" For this lens, the answer is clearly yes.
For the camera body, the calculation is different. Camera bodies depreciate faster, so the resale value component is smaller. But the higher rental income often compensates. You need to run both numbers for each item to see the full picture.
Annualized ROI: comparing across different holding periods
If you want to compare items you've owned for different lengths of time, annualize the return.
Annualized ROI = Total Return / Years Held
The lens at 35.8% total return over 2 years has an annualized ROI of 17.9% per year.
A monitor purchased for $500 that earned $380 in rental income over one year with a current resale value of $350 has:
Total Return = ($380 + $350 - $500) / $500 = 46.0%
Annualized ROI = 46.0% / 1 year = 46.0% per year.
The monitor is producing a higher annualized return than the lens, despite earning less in absolute dollars. This is the advantage of lower-cost items: the purchase cost is easier to clear, and the returns as a percentage are often higher.
The metrics that matter for different decisions
Different questions require different numbers.
"Should I keep renting this item?" Look at current booking frequency and monthly earnings. If it's still booking regularly and earning meaningful income, keep it listed. Past ROI is informative but the forward-looking question is whether it will continue to earn.
"Should I sell this item?" Compare remaining payback gap versus depreciation trajectory. If an item is at 40% payback and depreciating faster than it's earning, selling now and reinvesting might be the better move. If it's at 90% payback, hold until it crosses 100% and then reassess.
"Should I buy more gear like this?" Look at annualized ROI and booking frequency. Having a pricing formula that works ensures you are maximizing what each item earns. Items with high annualized returns and consistent booking patterns are the template for future purchases.
"Which items are dragging my portfolio down?" Sort by payback percentage. Items below 20% after more than a year of listing are underperforming. Either they're priced wrong, in low demand, or were a bad purchase for the rental market.
Why this is hard to do manually
The math itself is simple. The hard part is getting accurate input numbers.
For single-item rentals, your Sharegrid CSV export gives you the net payout per transaction. Sum those up per item and you have total net earnings. But for package rentals where multiple items went out together, the CSV shows a single line with combined revenue. There's no per-item breakdown.
This means you need to either estimate the revenue split (inaccurate), cross-reference each package rental against your confirmation emails (tedious), or use a tool that does it automatically.
You also need to track purchase costs separately since Sharegrid doesn't store what you paid for your gear. And resale values require periodic lookup against current market prices, which change as new models release and gear ages.
Automating the calculation
Rental IQ handles all of this. Its payback tracking and ROI analytics do the math automatically. Import your Sharegrid CSV, connect your email for automatic package resolution, and enter your purchase costs once. The platform calculates payback percentage, total return, annualized ROI, and per-item net earnings automatically.
Every number updates as new rentals come in. You don't need to maintain a spreadsheet or remember to re-export your data. The goal is to give you the same level of financial visibility that a real investment portfolio provides, applied to your camera gear.
The math is straightforward. The hard part has always been getting the right numbers into the formula. That's the problem worth solving.
